You use the toilet to eliminate waste matter from your body. When these actions appear in your dreams it is your unconscious highlighting your need to let go of emotional waste - generally old, unhappy memories or behaviours that are no longer serving you.
• Toilet dreams also refer to your basic needs in life and how these needs are or, are not, being met. Are you too busy to deal with your pent up emotions? Or are you being over emotional and dumping too much on your friends and family? Toilet dreams do, on occasion, indicate a genuine physical need and you’ll wake wanting to pee.... The Premier in Dream Dictionary